EUROFIX: definition and current status

Willigen, Durk van; Offermans, Gerard; Helwig, Arthur

doi:10.1109/plans.1998.669877

Cited by 6 publications

(5 citation statements)

References 4 publications

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“…The EUROFIX modulation scheme uses the last six pulses of the Loran-C pulse group. These pulses are pulse position modulated by ±1 μs (1 μs advance, a prompt, or 1 μs delay) [ 13 ], as shown in Figure 2 . To minimize the impact to users, PPM encoding uses 128 of the possible 141 balanced patterns to represent seven bits of data per group repetition interval (GRI).…”

Section: Methodsmentioning

confidence: 99%

“…The BT, which is obtained through data demodulation, refers to the time interval between the start time of the current Loran-C pulse group signal and the standard time. Currently, the international standard Loran-C signal system typically uses EUROFIX technology for data dissemination [12,13]. The EUROFIX datalink is implemented by an additional three-level pulse position modulation (PPM) of the Loran-C pulses.…”

Section: Introductionmentioning

confidence: 99%

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Demodulation Method for Loran-C at Low SNR Based on Envelope Correlation–Phase Detection

Yuan

Yan

et al. 2020

Sensors

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Loran-C is the most important backup and supplement system for the global navigation satellite system (GNSS). However, existing Loran-C demodulation methods are easily affected by noise and skywave interference (SWI). Therefore, this article proposes a demodulation method based on Loran-C pulse envelope correlation–phase detection (EC–PD), in which EC has two implementation schemes, namely moving average-cross correlation and matched correlation, to reduce the effects of noise and SWI. The mathematical models of the EC, calculation of the signal-to-noise ratio (SNR) gain, and selection of the EC schemes are given. The simulation results show that compared with an existing method, the proposed method has clear advantages: (1) The demodulation SNR threshold under Gaussian channel is only −2 dB, a reduction of 12.5 dB; (2) The probability of the demodulated SNR threshold, being less than zero under the SWI environment, can reach 0.78, a 26-fold increase. The test results show that the average data availability of the proposed method is 3.3 times higher than that of the existing method. Thus, our demodulation method has higher engineering application value. This will improve the performance of the modern Loran-C system, making it a more reliable backup for the GNSS.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Demodulation Method for Loran-C at Low SNR Based on Envelope Correlation–Phase Detection

Yuan

Yan

et al. 2020

Sensors

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“…The signal received by eLoran system in complex environment includes direct ground‐wave, one‐hop sky‐wave, multi‐hop sky‐wave, signal from other Loran station low‐frequency interference and noise [19, 20]. It is considered that the multi‐hop sky‐wave has the characteristics of large amplitude attenuation and high delay and low frequency interference is easy to remove.…”

Section: Signal Model For Complex Environmentsmentioning

confidence: 99%

ELoran signal message prediction algorithm based on Alexnet‐ECA

Zhang,

Yang,

Wang

et al. 2023

IET Radar Sonar & Navi

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Enhanced Loran (eLoran) is the most important backup system for Global Navigation Satellite System (GNSS). However, most current eLoran demodulation methods are based on digital signal processing, which may produce large errors under the influence of strong interference or noise. The authors propose an eLoran signal message prediction algorithm based on deep learning. Using time‐frequency (TF) analysis convert one‐dimensional signal into two‐dimensional high‐resolution image. It improves Alexnet by adjusting the convolutional layer structure, adding an attention module, and reducing the pooling layer window to construct the Alexnet‐ECA network. The network is used to identify TF image features and predict signal message. The experimental results show that novel method for eLoran signal message prediction based on Alexnet‐ECA can achieve high accuracy and robustness in various SNR scenarios. The accuracy is more than 90% at SNR greater than 10db and not less than 80% even in the complex environments. Compared with Resnet34 and VGG16 networks, Alexnet‐ECA demonstrates its efficiency and effectiveness using real measurement data. This method can enhance the performance and reliability of eLoran receivers and applications.

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“…It utilizes the characteristics of stable ground wave propagation and the accurate prediction of the propagation delay of long wave signals for a highly precise service. It also undertakes GNSS timing backup, supplementation, and enhancement, as well as satellite ground fusion timing applications [17][18][19][20][21].…”

Section: Principle Of Eloran Time Service Systemmentioning

confidence: 99%

Analysis of the Development Status of eLoran Time Service System in China

Yang,

Li,

2023

Applied Sciences

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This article introduces the eLoran timing system principle, the characteristics of the eLoran and GNSS systems, and the current development status of eLoran in China. This article elaborates on the significance and scale of this high-precision ground time service system currently being constructed in China and describes the technical methods used in the high-precision ground time service system. Finally, it analyzes and elaborates on the signal and data channels of the eLoran time service system.

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EUROFIX: definition and current status

Cited by 6 publications

References 4 publications

Demodulation Method for Loran-C at Low SNR Based on Envelope Correlation–Phase Detection

Demodulation Method for Loran-C at Low SNR Based on Envelope Correlation–Phase Detection

ELoran signal message prediction algorithm based on Alexnet‐ECA

Analysis of the Development Status of eLoran Time Service System in China

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